Actually all you need remove to disable automatic idle speed circuit is the short piece of hose connecting motor to cold start tube. That's all. (Of course loose ends need to be plugged with vacuum caps). And nothing needs to be added -- manual screws are already in manifold. Furthermore, you can jump back and forth between the two simply by tightening screws and putting short hose back. I do recommend replacing O rings on the brass screws to ensure vacuum tight (bottoms are tapered into seats so this isn't an issue when snugged down). Note that throttle plate microswitch also activates spark advance cut off solenoid. If it doesn't work, car will be way over advanced at idle. Vacuum chambers on CPR only respond to sudden CHANGE in vacuum, so they can't help. Sometimes wonder how many owners are cranking mess out of fuel mixture screw trying to get RPM's down when problem is actually ignition timing (over advance). Bill Robertson #5939 > > Now if the manual by-pass on your car works, and you're happy with it, then= > > by all means, go with what you're most comfortable with. However, for futur= > e > referance, you might want to spend a few minutes making sure that the > Microswitch is being fully depressed before ripping out/moddifying the enti= > re > Idle Speed Ciruit. It's a helluva lot easier, and cheaper! > > -Robert > vin 6585 "X"